High Impedance Fault Detection in Microgrid Using Sum of Difference Method

High Impedance fault (HIF) in microgrid increases risk of fire and risk to the life of people. The commonly employed overcurrent relays in distribution network are inefficient in detecting HIF due to its peculiar characteristics. The small fault current magnitude, nonlinear nature, random behavior and the over-current relay is unresponsive to the highly fluctuating fault current. Further, the different operating conditions of microgrid complicate the protection issues. The paper proposes a Sum of Difference in Current (SDI) based HIF detection technique for microgrid considering different operating conditions. Further, the proposed scheme has been analyzed considering different fault and no-fault events to show its efficacy for safe and reliable functioning of micro-grid.